The present invention relates to a technique for preparing hydrogen cyanide by the ammoxidation of methanol, formaldehyde and/or dimethylether.
It is already known that methanol can be ammoxidized to HCN using various oxide complex catalysts. See, for example, Japanese published applications: Nos. J76-10,200, J76-11,100, J76-99,700, J78-149,899 J78-149,900, J79-126,698, J79-69,597, J79-76,500 and J79-71,799. Molybdates, antimonates and tungstates serve as catalysts in these processes.
Although these patents indicate that HCN can be produced in high yields, close examination shows that the processes are conducted under very mild conditions. As well appreciated by those skilled in catalysis, the ability of a catalyst to convert reactant into desired product decreases as the amount of reactant per unit weight of catalyst per unit time (i.e. throughput) increases. The processes described in the above noted Japanese published applications have very low reactant throughputs meaning that a large amount of expensive catalyst is necessary to produce a given amount of product.
Accordingly, it is an object of the present invention to provide a new process for ammoxidizing methanol as well as formaldehyde and dimethylether to HCN which employs a catalyst capable of giving good yields of HCN at high reactant throughput.